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Thé résistance is a thick film on ceramic substrate forming the attenuator It includes a thermistor to sense overload Abuse of the input fries both 50 ohm and thermistor Place ohms meter on

Hello the tracking Gen was a mod kit and only available in limited qty. 99% of 7L5 had none and some came with the option installed You find complete 7L5 on eBay and ham fleas, suggest you look for

Check blanking and Z axis. J

Dear Wilford, bravo for your work, very sorry for the problems ....but an old story. Such vintage scopes are 1970s..1980s ( check serial, parts date codes). So, common that insulation,

Hello, Some bad news, I'm afraid. Yesterday evening everything looked all right and sharp, but at some point the picture went unstable and way out of focus, I could also hear some strange noises

Yes, it is exactly what happened. The resistor burned, the big capacitor also destroyed and the BUZ355 cracked along with a few other components like the VR9. I did read about not having it in standby

Thanks that is very good information. My guess would have been in the 20V but this is better. Thanks a lot.

That's not something I would associate with the CRT Bias setting. In your image, retrace blanking seemed to be incomplete. Trying to adjust CRT Bias won't harm though... Raymond

Reply to Raymond Haven't opened it yet. But I guess I'll have to try it one of these days.

Reply to Nenad: The pattern is random, jumps around. The sine wave was at 1 kHz so I tried a few different time base settings ( don't remember which ones ) but it was showing in all of them I

Especially looking at the start of the trace, it could simply be a matter of CRT bias adjustment. Simple to do and undo visually and no loss of calibration. Raymond

Hello *, is there a way to the set the probe attenuation manually on that scopes which dont't have a "Probe Functions" menu like the C or D models? If there is no digital way are there any solutions

Looks like a noisy contact in the X signal path. Is the pattern stable or intermittent? How fast was the sweep speed you used when you took the photo? Does it react if you fiddle with the timebase

I have a problem with horizontal display showing double or distorted image . It happens on both channels and I uploaded a photo in the album named : 485 Problem If anyone has seen something similar

I noticed on your picture that the large ceramic resistor has burned the board. This is/was a common problem on these supplies. It was due to too high voltage across the resistor when in standby mode.

With one end removed from the board and checked on a 576 curve tracer it has zener voltage of 17.4V /H?kan

The 485 is not a storage 'scope. It is the successor to the 465/475 line. The 485 is a 350 MHz 'scope, and an excellent 'scope. The 464 is a storage 'scope. Covers for the 485 are extremely rare.

I have inherited both a Tek 464 scope and a Tek 485 storage scope. I've been using Teks since 1966. I'm looking for the plastic covers for the front panels of both. Both came to me without probes.

Good morning, Thank you all for the support, I will follow up and let you know. Wilfred

added some pictures for the VR9 ZENER diode that I can't find value on as blown and no schematics.